1. Field of the Invention
The present invention relates to an aberration correction element for making an aberration correction in recording or reproducing information with respect to an information recording medium, such as a DVD, and an optical pickup and an information equipment which are provided with the aberration correction element.
2. Description of the Related Art
An information recording medium on which the data is recorded or reproduced by using laser light or the like has been developed, which is, for example, a CD, a DVD, or the like. In such optical recording or reproduction of the data by using the laser light, it is hardly possible to appropriately perform the recording and reproduction if the influence of coma aberration or spherical aberration or the like is not eliminated.
In order to correct the coma aberration, which is caused by the presence of the tilt of the information recording medium, an a laser element which emits laser light has been developed, for example. Moreover, there has been recently developed an optical pickup that eliminates the influence of the coma aberration and the spherical aberration, more preferably, by using an aberration correction element which uses the change of the refractive index of a liquid crystal element. Furthermore, in order to correct the spherical aberration more preferably, which is unevenly caused in the range of the irradiation spot of the laser light, an optical pickup that uses an aberration correction element having such a structure that a liquid crystal element is sandwiched by a plurality of multilayer electrodes has been developed by the inventors of the present invention and the like (refer to Japanese Patent Application Laid Open No. 2001-176180).